I've ridden a Surly Pugsley & a Ti Fatback. They ride wonderfully. Lower rolling resistance than I would imagine & roll over roots & rocks with ease. The owner of the Ti Fatback had just ridden a hilly road century on it. No, 5psi is not torture on those tires. Faster than a beach cruiser, slower than a time trial bike! Except in its element, where it might be the fastest. As far as rust on the Surly from salt, the powder coat is very good and if you treat the inside of the tubes with framesaver, then even better. However, the Ti Fatback (with the exception of the steel fork) would eliminate that issue.